This patent application claims the benefit of priority under 35 U.S.C. xc2xa7119(a) of Dutch Patent Application No. 1012637, filed Jul. 19, 1999. Dutch Patent Application No. 1012637 is herein incorporated herein in its entirety by reference.
The invention relates to a heat exchanger provided with a housing having an inner wall, an inlet and an outlet for passing a first heart exchange medium through the housing, having a core, comprising a series of plate-shaped fins placed at least almost parallel to each other, in which each fin is provided with pipe openings, and a bundle of pipes for passing a second heat exchange medium, and a number of baffle plates, in which each baffle plate is provided with pipe openings, in which each of the pipes extends through respective pipe openings of respective fins and respective baffle plates.
Such a heat exchanger is known from Dutch patent application 9500633. Although the known heat exchanger functions well, in some situations the operation may not be optimal. In said known heat exchanger, the baffle plates are namely situated loose against the inner wall of the housing, and the baffle plates only obtain their rigidity because the pipes pass through them. As a result, there is not only a chance that a quantity of first heat exchange medium, for instance oil, leaks through between the baffle plate and the inner wall of the housing, but there is also a chance that as a result of repetitive occurrence of pressure blasts the first heat exchange medium is subjected to, for instance during the cold start of motors, valves turn over and suchlike, unwanted bending of the baffle plates arises.
It is an objective of the present invention to provide a heat exchanger in which the above-mentioned problems are solved.
To that end, a heat exchanger of the kind mentioned above according to the present invention is characterized by filling blocks being provided, each having a bent base portion which has an outer surface, the bend of the base portion being such that the filling block closely abuts the inner wall of the housing, with a rib projecting from the base portion to the centre of the housing when placed in the housing, which rib has a central slot, in which slot a respective baffle plate is accommodated. Said filling block ensures that when a possible radial change of position occurs between the baffle plate and the inner wall of the housing, no leakage of the first heat exchange medium occurs. It is noted here that as a result of the pressure of the first heat exchange medium, the filling block is pressed against the inner wall of the housing. Furthermore the filling block increases the resistance of the baffle plates against bending, for instance as a result of pressure blasts.
In a preferred embodiment of a heat exchanger according to the invention, at least one of the filling blocks is made of elastic material. Preferably, the elastic material is a material that is resistant to the commonly used first heat exchange media, such as for instance mineral oils. As a result, in some cases, an improved absorbtion of pressure blasts active on the baffle plates and a further reduction of leakage is realized.
Preferably, at least one of the filing blocks is made of aluminum or an aluminum alloy. Said materials are extremely resistant to the commonly used first heat exchange media.
In order to obtain a correct pressing of the outer surface of the base portion against the inner wall of the housing, according to an embodiment of the invention, at least one of the filling blocks is provided with a spring which is situated in the slot between the baffle plate concerned and the bottom of the slot.
A further improved pressing of the filling block against the inner wall of the housing is obtained when the outer surface of the base portion of at least one of the filling blocks shows two different curvature radiuses R1, R2, in which R1 is the curvature radius of the central part of the base portion, R2 is the curvature radius of the parts of the base portion that are situated outside of the central part, R1 being larger than R2. Preferably the curvature radiuses have different centres.
Preferably, the projecting rib is provided with a bore hole, for accommodating an attachment means for attaching a filling block to the baffle plate concerned.
Some embodiments of a heat exchanger according to the present invention will by way of example be described on the basis of the drawing.